北京地区Noro病毒主要衣壳蛋白编码基因的序列分析

Sequence analysis for the major capsid protein genes of Noroviruses identified from specimens collected from children with diarrhea in Beijing

目的 确定从北京地区婴幼儿腹泻标本中检测到的3株Noro病毒的基因型别及主要衣壳蛋白（VP1）编码基因的特点。方法 从经酶免疫分析法筛选到的Noro病毒阳性的粪便标本中应用RT-PCR方法扩增Noro病毒VP1全基因，克隆到pBS-T载体中并测定核苷酸序列，与GenBank中的其他Noro病毒VP1基因序列进行比较和分析。结果 经过扩增和测序，标本CR2905、CR2932和CR2987的VP1基因全长分别为1620bp、1623bp和1647bp，编码不同大小的蛋白。CR2905和CR2932与GⅡ-4型的氨基酸同源性在80％以上，属于Noro病毒GⅡ基因组（Genogroup）的GⅡ-4型（Geno．type）；CR2987与GⅡ-3型的氨基酸同源性在80％以上，属于Noro病毒GⅡ基因组的GⅡ-3型。CR2905、CR2932与其他GⅡ-4型的变异性在9．1％至12．5％之间，提示为新的变异株。结论 北京地区婴幼儿中存在不同基因型别的Noro病毒的感染，根据基因的同源性分析，CR2905、CR2932可能为GⅡ-4型的新的变异株。

Objective To identify the＇genotype of the Norovirus circulating in Beijing through sequence analysis. Methods RT-PCR was performed in this study to obtain the full-length eDNA of major capsid protein gene of Norovirus from Norovirus positive samples screened by enzyme immunoassay（EIA） for human ealieiviruses. PCR products were cloned into the vector pBS-T. The sequences were compared with the sequences of Noroviruses selected from the GenBank. Results Full length VP1 genes were obtained from 3 cliniced speeimens with ID humors of CR2905, CR2932 and CR2987. The genes were 1620 bp, 1623 bp and 1647 bp in length, respective- ly. The complete capsid amino acid sequence of CB2905 and CR2932 shared more than 80.0% identities with the GH -4 strains in the GenBank, indicating that they were G H -4 genotype; that of CR2987 shared more than 80.0% identity with the G H -3 strains, indicating that it was G H -3 genotype. The amino acid divergence of the complete capsid gene between CB2905, CB2932 and other G H -4 Norovims in GenBank were 9.1%-12.5%, suggesting that they may be defined as new variants. Condusion Noroviruscs with difference genotypes were circulating in young children with diarrhea in Beijing, China. CR2905 and CR2932 may be defined as new variants from G Ⅱ -4 genotype.